Fusible link.



F. VIGTMANN. PUSIBLE LINK. APPLIUATION FILED Nov. 16, 1908.

1,017,715. Patented Feb.20,1-9172;

'quickly than links of the coiistruotion now UNITED STATESPATENT OFFICE.

FRANK VOIGTMANN, OF CHICAGO, ILLINOIS.

FUSIBLE LINK.

Application tiled November i6, i998.

This invention relates to innirovements in fusible links ot the general type employed for automatically releasing tire doors, winA dows, etc., whenever the temperature rises above a predetermined height.

The salient object. oi" the ilnesont inveniiion is to provide a link which. while amply strong t0 sustain the draft or pull thereon is more sensitive to heat, and rises to the predetermined releasing tennieraturo more m common use.

Subordinant objects of the invention are to provide a construetion which is of eX- tremely low cost and the parts ot' which may be accurately united by careless or unskilled labor.

The invention consists in the matters herelmatter described, and more particularly pointed out in the appended claims.

In the drawing-Figure l is a plan or top side view of a link en'ibodying my invention; Fig. 2 is a central longitudinal section; Fig. 3 is a central transverse section,

In Constructing my improved link.l employ sheet'metal ot' a relatively thin gage,- thinner than would be sutiieient to sustain 4the mechanical stresses, except t'or the tart that the two members are overlapped and. dished together as to the ohiet portions of the link in such manner as to oonibine the strengtl'i of the two parts. As an example, prefer to employ tor making u link inches long, and Capable ot safely sust-aining a draft up to l5() pounds, sheet bronze of thirty gage. Each link is composed ot two stampings, as l. and 2, which may be, and preferably are, exart (.-oiniterlinirts ot each other; each stamping comprising, 'in the preferred embodin'ient shown, a mutilated main central ring portion 3 and an unmutilated smaller ring-shaped loop or eyelet 4 formed integrally with the main ring. The main ring of each member is cut away at. its side diametrically opposite the loop or eyelet 4, as indicated at 5, in, such manner that when the two link members are placedr Specification of Letters 'atent.

Patented Feb. 20', 1912.

Serial No. 462,954.

le ve.le.t portions 4- will projeet beyond the ovfffrlabbed portions at each end. rThe overlapped portions obviously when soldered together combine toa large extent the. strength ot both members` and in order that the eycht portions which are not overlapped may he approximately as strong as the overlapped portions` l reintorre these smaller with metal eyelets. as these eyelets heilig provided with broad underlying tlanges 7 which lit inside the roneave portions ot the members l while their upper edges are clamped over the peripheries otI the opening. as indicated atI 8.

ks one. ot' the most importiint teatiufes ot the prese-nt, invention l resort toa method ot soldering the link nielnliers together which Lhave discovered, and which has been Found to make thel link farmore sensitive to heat and more unitorm in its fusing temperature than the links of the prior art. This method ot soldering referred to consists in -iirst properly (.fleaning 4the inen'ibers ot the link', so that. solder will readily adhere, by any suitable means, as for example. by cleansing with a. proper arid, then assembling the links in proper relation to eath other, and, while holding the membersl pressed together with a suitable. tool,` dipping them momentarily bodily in a bath ot the solder. withdrawing them .and immediaiolj,V plunging medium.

The tool by which the link members are held while. being submerged or dipped in the bath ot molten solder may conveniently be a pair ot' tongs or pinoers Aprovided with ot engagement with the link are small and the solder, therefore, permitted to rover practically the entire surface of the device. The dipping ot the links into a cooling bath while possilily not essential to good results, nevertheless results in soliditfying the solder while it. is evenly spread upon the parts and precludes its tendency to creep or gather into lumps at various points while solidifying slowly. This step of the process', there fore, renders the links more uniform as to their fusing points. These links in prac-- "tical use usually become coated with soot, dust, etc., and it is the practice of underwriters to approximate conditions of practical use when testing such links -by artitioially coating them with calcimine, white-- rings by eyeleting the openings thereofv the link in water or other suitable AehillingV pointed teeth or jaws, sothat their points Wash or some analogous wash, and allowing them to dry before subjecting them to the fusing test. Such tests have demonstrated beyond question of doubt that the links constructed as described herein, and soldered by dipping them in a bath of molten solder, are many degrees more sensitive than links of the prior art, and are very considerably more sensitive than links constructed identically as described,.except that they are simply soldered together in the usual way, z'. e., by'applying solder to the meeting joints only. I am unable to account with certainty for this fact', but it may be due to one or more of the following causes, viz: by reason of the tendencyv of the fusing action toV spreadrapidly through the solder as soon as it begins to fuse at any one point, it may be that the exposure of so large -an area of solder insures that some one or another will begin .tofuse at an earlier stage than would otherwise'be the case and that t-he entire fusion follows more quickly thereafter, or by reason of the manner in which the parts are held together while being dipped in the molten bath and chilled promptly after removal, the film of solder may be consider- .ably thinner than that secured by ordinary methods, and for this reason the link made more sensitive, or the conductivity for heat of the film of solder may be greater than that ofthe underlying harder metaLand because of the larger surface of solder exposed. to the heat, the fusing promoted.

While I have herein shown and described a preferred embodiment of the invention, and shown a construction which possesses in the mere matter of structure Well defined improvements over the links of the prior art, nevertheless within the broader scope of the invention it may be otherwise embodied without departing from the spirit thereof. Accordingly I have claimed the device both broadly and specifically.

I claim as my invention:

1. A fusibly-separable link composed of two relatively thin sheet metal members, partially overlapped and united by a film of solder extending between them, the overlapping portions being stamped .into similar intaglioreliefsurface patterns and internestecL and the non-overlapped apertured ends of the device provided with metal reinforcements.

2. The combination with two thin sheetlike members partially overlapped and internested as to their overlapping portions and forming when united athin relatively flat sheet-like link, said members being provided at their free outer. ends with closed loop portions, and a lm of solder incasing the -exterior of said links, and extending between and uniting the overlapping portion.

3. A fusibly-separable link composed of two thin sheet metal members, partially overlapped and united by a film of solder lying between them, the overlapping portions being stamped into similar intaglio-relief surface patterns and internested, and

thc openings in the extremities ofl the link reinforced by eyelets.

4. A fusibly-separable link composedv of two substantially ident-ical thin sheet metal members, each comprising agenerally ringshaped main body and a generally. ring shaped terminal loop, each ring portion being stamped into concavo convex form in radial section, the main bodies of the two members being overlapped and internested and united by a film of solder.

5. A fusibly-separable link composed of two thin sheet metal members, each comprising a generally ring-shaped mainA body and a smaller generally ringshaped terminal loop, each ring-shaped main body being stamped into concavo convex form in radialsection, the main bodies of the two members overlapped'. and internested, and the parts united by a film extending between the overlapped portions and covered with a coating of solder.

FRANK VOIGTMANN.

Witnesses:

F. L. BELKNAP, EMiLm ROSE. 

